I won't be re assigning. Just removing rears from the amp and using the recievers built in amp.I'd preffer to keep it simple while I test the theory.The simplest would be to run them off the receivers single output with a paired cable.The recievers only powering the center and presence now. Theres headroom available.Would running 2 8ohm speakers mean a 4ohm load?

Almost no one (aside from CatBrat) does what you are proposing, which, if I understand it correctly, is running two pairs of L/R fronts. There is no second center output on any receiver I know of, so if you're talking about running dual centers, your question is moot.

I would be using 2 channels from the amp if I did.The reciever could handle the load though.I like to swap speakers. Looking at the cost of the stand and new center it almost makes sense to add another pair of M80's. I will work my old towers back into L /R and will try the dual 80's for a while. It won't be for a while though.I'd like to hear Brians setup too. I like how my layout sounds but the center has to go. It will join the parts pile asap.

I'd be running 2 QS4's or QS8's off one(receiver or amp). I'm not sure if having the empty channel on the amp would have any benifit except that at 4 ohm I should have more potential headroom.M80's would be on seperate channels from the amp. Always will be.

Almost no one (aside from CatBrat) does what you are proposing, which, if I understand it correctly, is running two pairs of L/R fronts. There is no second center output on any receiver I know of, so if you're talking about running dual centers, your question is moot.